Industrial Pneumoconiosis Prevention and Control

Our plain-English summary of Industrial Pneumoconiosis Prevention and Control, by E.M. Fenner (1969).

The study

• Author: E.M. Fenner
• Published: The Joint Session on Chest Diseases and Clinical Pathology of the Medical Society of New Jersey. May 19th 1969
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This is not a research study. It is the text of a talk given on May 19, 1969, at Atlantic City before the Medical Society of New Jersey by the director of environmental control at Johns-Manville. The author, an engineer, described the company's dust control program in its plants and mines and said the company had 22,000 employees. The author said asbestos fiber dust had been judged against a limit of 5 million particles per cubic foot of air, plus a company limit of 1 million fibers, 10 microns or longer, per cubic foot. The company then adopted a membrane filter method that counted fibers by microscope. As an example, the author said a new dust control system costing about $125,000 at the asbestos-cement shingle operation at the Manville, New Jersey plant brought dust below both limits. The author acknowledged that not every situation was under control. The author concluded that prevention depends on designing equipment to be free of hazardous dust emissions, on regular dust surveys, and on respirators only when other control is impossible.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Conference talk by an industry engineer describing the author's company's dust control program. It is not a research study, and no health outcomes were measured
• Who was studied: No study population. The talk concerned working conditions in Johns-Manville plants and mines. The author referred to the company's 22,000 employees
• Exposure: Respirable dusts in Johns-Manville plants and mines, mainly asbestos fiber dust. The company also monitored diatomaceous earth, crystalline silica, talc and mica. The worked example was an asbestos-cement shingle-making operation
• Main results:
  • The author said the Threshold Limit Value for asbestos fiber dusts had long been 5 million particles per cubic foot, set by the American Conference of Governmental Industrial Hygienists in the 1930s. Johns-Manville also used a limit of 1 million fibers per cubic foot recommended by doctors at Saranac Lake
  • The author described a newer ACGIH value of either 2 million particles per cubic foot of air or 12 asbestos fibers over 6 microns in length per cubic centimeter of air. Later in the talk the author called this a proposed TLV
  • The company adopted a method recommended by the Public Health Service. A personal air sampler collected dust on a membrane filter, and fibers were counted by phase contrast light microscopy at 430 magnification
  • Each Johns-Manville plant had a complete industrial hygiene survey at least once a year. Operations with potentially higher exposures were surveyed more often
  • The shingle-making operation at the Manville, New Jersey plant was revised in 1966, and a new dust control system costing about $125,000 was then installed. The author said re-surveys showed it reduced dust levels below both the ACGIH and Johns-Manville limits. The plant was being resurveyed against the proposed limit of 12 fibers per cubic centimeter
  • The author stated that the company did not have every situation under control at that time
• The authors' conclusion: The author concluded that preventing industrial pneumoconiosis depends on two things: processes and equipment designed to be free of hazardous dust emissions, often with engineered dust collection, and formal dust surveys with corrective action when levels exceed the TLV. In the author's view, respirators approved by the U.S. Bureau of Mines should be relied on only when dust cannot be controlled otherwise. The author also expressed the view that the company's approach would in time eliminate industrial pneumoconiosis in its plants and mines

Topics

Medical terms in this study, explained in our Lexicon: Pneumoconiosis, Johns-Manville, Dust Control, Million Particles per Cubic Foot (mppcf), Membrane Filter Method, Asbestos-Cement, Respirator.

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